Although some conventional liquid valves permit control of liquid temperature and volume flow rate by adjustment of a single control handle, they do so at the expense of requiring many components that are hard to manufacture and maintain, and often call for specialized maintenance personnel to perform many required repair and maintenance tasks. Furthermore, in bathroom installations wherein a shower head as well as a bathtub is being supplied with water, an additional water faucet capable of controlling temperature and flow rate of water supplied to the shower head must typically be installed, requiring a rather complicated arrangement which leads to waste of time, money and space.